A plasma processing apparatus has a plasma processing chamber that accommodates an electrode pair of a plasma excitation electrode for exciting plasma and a susceptor electrode facing the plasma excitation electrode, a workpiece to be treated being placed therebetween. The apparatus also has a chassis that accommodates an impedance matching circuit, provided in the middle of a supply path for feeding rf power from an rf generator to the plasma excitation electrode, for matching the impedance between the rf generator and the plasma processing chamber. In the chassis, impedances are axisymmetrically equal at a predetermined frequency with respect to the direction of a high-frequency current returning to the rf generator. The matching circuit has at least two inductance coils connected in parallel.
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11. A plasma processing apparatus comprising:
a plasma processing chamber having an electrode for exciting plasma; an rf generator for supplying the electrode with rf power; and a matching circuit having an input terminal and an output terminal, for matching the impedance between the plasma processing chamber and the rf generator, the rf generator being connected to the input terminal, the electrode being connected to an rf feeder and the rf feeder being connected to the output terminal, the rf feeder having a central axis wherein the matching circuit includes at least two inductance coils electrically connected in parallel, and positioned such that the at least three inductance coils form the vertices of a regularly shaped polygon in a plane perpendicular to the central axis of the rf feeder, the center of the polygon coinciding with the central axis of the rf feeder.
1. A plasma processing apparatus comprising:
a plasma processing chamber that accommodates an electrode pair of a plasma excitation electrode for exciting plasma and a susceptor electrode facing the plasma excitation electrode, a workpiece to be plasma-treated being placed therebetween; and a chassis that accommodates an impedance matching circuit, provided in the middle of a supply path for feeding rf power from an rf generator to the plasma excitation electrode, for matching the impedance between the rf generator and the plasma processing chamber, the chassis serving as a return path from the susceptor electrode to the rf generator and further comprising adjusting means for making the chassis impedances axisymmetric about the central axis of the chassis; wherein, in the return path in the chassis, impedances are axisymmetrically equal at a predetermined frequency of the rf power with respect to the direction of a current returning to the rf generator.
19. A plasma processing apparatus comprising:
a plasma processing chamber that accommodates an electrode pair of a plasma excitation electrode for exciting plasma and a susceptor electrode facing the plasma excitation electrode, a workpiece to be plasma-treated being placed therebetween; and a chassis that accommodates an impedance matching circuit, provided in the middle of a supply path for feeding rf power from an rf generator to the plasma excitation electrode, for matching the impedance between the rf generator and the plasma processing chamber, the chassis having a central axis and serving as a return path from the susceptor electrode to the rf generator, wherein the surfaces of the chassis are formed such that impedances presented on the surface of the chassis in the direction of current returning to the rf generator and at a predetermined frequency of the rf power are axisymmetric with respect to the central axis of the chassis, the formation of the chassis comprising selecting the quality of the material of the chassis to have a uniform impedance with respect to a high frequency current at a predetermined frequency and providing the shape of the chassis such that a cross section of the chassis perpendicular to the central axis of the chassis has a shape of one of a regular polygon or circle.
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1. Field of the Invention
The present invention relates to plasma processing apparatuses. More particularly, it relates to a plasma processing apparatus which, during plasma discharge, is capable of preventing drift of a discharge current that flows through a gap between electrodes of an electrode pair and further is capable of increasing the effective electrical power in a plasma space.
2. Description of the Related Art
RF power transmitted from the output of the RF generator 1 is sequentially fed into the plasma excitation electrode 4 through the matching circuit 2A and the RF feeder 3. A shower plate 5 having many holes 7 is in contact with projections 4a on the bottom face of the plasma excitation electrode (cathode) 4. A gas inlet pipe 17 communicates with a space 6 formed between the plasma excitation electrode 4 and the shower plate 5. An insulator 17a is provided in the middle of the gas inlet pipe 17, which is made of a conductive material, to insulate the plasma excitation electrode 4 from the gas supply source. Gas from the gas inlet pipe 17 is introduced into a chamber 60 surrounded by a chamber wall 10 through the holes 7 of the shower plate 5. The upper side of the chamber wall 10 and the plasma excitation electrode 4 are hermetically sealed with an insulator 9 interposed therebetween.
The susceptor electrode 8 is provided in the chamber 60 and serves as the common (i.e., ground) side of the discharge voltage. A workpiece W, such as a wafer, is placed thereon. A shaft 13 supports the susceptor electrode 8. The lower portion of the shaft 13 and a chamber bottom 10A are hermetically sealed with conductive bellows 11. Air is exhausted from the chamber 60 by an exhaust system (not shown).
Since the susceptor electrode 8 can move vertically together with the shaft 13 and the bellows 11, the distance between the plasma excitation electrode 4 and the susceptor electrode 8 can be adjusted while maintaining a vacuum in the chamber 60. The lower portion of the shaft 13 is grounded, and the common side of the RF generator 1 is also grounded. The chamber wall 10 has the same DC potential as that of the shaft 13.
Referring to
In general, in the plasma processing apparatus described above, when drift occurs in a high-frequency current flowing through the gap between the plasma excitation electrode 4 and the susceptor electrode 8 during discharge, the plasma density within the plasma processing chamber 60 changes, resulting in a non-uniform plasma treatment of the workpiece W. Furthermore, the plasma processing apparatus described above has an additional disadvantage of large power loss in the matching circuit due to high parasitic RF resistance in the inductance coil in the matching circuit.
Accordingly, what is needed is an improved plasma processing apparatus which avoids the non-uniform plasma treatment.
Accordingly, embodiments of the present invention provide a plasma processing apparatus capable of performing uniform plasma treatment of the treatment surface of a workpiece.
Further, by lowering the parasitic RF resistance in an inductance coil of the matching circuit, embodiments of the present invention provide a plasma processing apparatus capable of increasing the plasma-processing capacity by reducing the power loss in a matching circuit and increasing the effective power in a plasma space.
The present invention, in its first aspect, provides a plasma processing apparatus having a plasma processing chamber that accommodates an electrode pair, the electrode pair including a plasma excitation electrode for exciting plasma and a susceptor electrode facing the plasma excitation electrode. A workpiece to be plasma-treated is placed between the electrodes. The plasma processing apparatus further includes a chassis that accommodates an impedance matching circuit, provided in the middle of a supply path for feeding RF power from an RF generator to the plasma excitation electrode. The impedance matching circuit functions matches the impedance between the RF generator and the plasma processing chamber. The chassis serves as a return path from the susceptor electrode to the RF generator. In the return path provided by the chassis, impedances are axisymmetrically equal at a predetermined frequency of the RF power with respect to the direction of a current returning to the RF generator.
While not wishing to be bound by any theory, it is believed that variation in plasma density in the plasma processing chamber is caused by drift in a high-frequency current flowing through the gap between the plasma excitation electrode and the susceptor electrode and that formation of a particular return current path in the chassis, which serves as a return path of the high-frequency current to the RF generator, causes the drift of the high-frequency current. In other words, the return current path particularly in the surface of the chassis is selectively formed along the portion having the lowest impedance at a predetermined frequency of the RF power used for plasma discharge. A discharge current flowing through the gap between the electrodes of the electrode pair varies in density such that the discharge current flows through the shortest path. Thus, making the impedances on the surface of the chassis axisymmetrically equal can prevent or suppress the drift in the gap between the electrodes of the electrode pair.
In accordance with embodiments of the present invention, the chassis may accommodate not only the impedance matching circuit but also other feeders such as an RF feeder from the impedance matching circuit to the plasma excitation electrode. The term "axisymmetric" mentioned above, which will be described below in detail, means not only the generally-defined state in which two points are disposed at equal distances from the central axis thereof on a straight line perpendicular to the central axis, but also the state in which a plurality of points are disposed at equal distances from the central axis thereof on a plane perpendicular to the central axis, the plurality of points also arranged with equal intervals between each other.
The cross-section of the chassis perpendicular to the central axis thereof preferably has a shape of a regular polygon or a circle.
When the quality of the material of the chassis is uniform with respect to the high-frequency current at a predetermined frequency, if the cross-section perpendicular to the central axis has a shape of a regular polygon or a circle, the impedances on the surface of the chassis are axisymmetrically equal with respect to the high-frequency current flowing along the central axis of the chassis. Therefore, the high-frequency current uniformly flows around the peripheral wall of the chassis, so that no deviated path is formed. Regular polygons mentioned above include, for example, not only a square or a regular hexagon, but also a regular triangle or a regular pentagon in accordance with the definition of "axisymmetrial" described above. The shape of the entire chassis is not limited to a regular polygonal prism or a cylinder. In accordance with embodiments of the present invention, the entire chassis may have a shape of a regular polygonal pyramid, a cone, a frustum of a regular polygonal pyramid, a frustum of a cone, a dome, or a combination of these shapes one on top of another and sharing one central axis.
When the quality of the material forming the chassis is not uniform with respect to the high-frequency current at a predetermined frequency or when the cross-section of the chassis does not have a shape of a regular polygon or a circle, the impedances can be adjusted so as to be axisymmetrically equal, for example, by providing slits or fins for adjusting the high-frequency current path in the chassis or by bonding a conductive component having different impedance to the chassis. That is adding or subtracting impedances, adjusting the high frequency current path, or both can be performed to achieve axisymmetry.
Preferably, the RF generator and the impedance matching circuit are connected with a coaxial cable wiring line extending from the center of the top of the chassis to the RF generator. It is also preferable that the plasma processing chamber be axisymmetrically formed and that the central axis thereof be coincident with the axis of symmetry of the impedances of the chassis. It is also preferable that the susceptor electrode be axisymmetrically formed and that the central axis thereof be coincident with the axis of symmetry of the impedances of the chassis.
The return path from the susceptor electrode to the RF generator is preferably formed such that the impedances at a predetermined frequency are axisymmetrically equal with respect to not only the chassis, but also the wiring line extending from the chassis to the RF generator; and, when the peripheral wall of the plasma processing chamber functions as the return path to the RF generator, also with respect to the peripheral wall of the plasma processing chamber and the susceptor electrode itself. It is also preferable that the wiring line extending from the chassis to the RF generator be a coaxial cable, the core of which is the outer path of the RF power and the shielding line of which is the inner path thereof, and that the wiring line extend from the center of the top of the chassis, that is, from a point coincident with the axis of symmetry of the impedances, to the RF generator. It is also preferable that the plasma processing chamber and the susceptor electrode be axisymmetrically formed and that respective central axes thereof be coincident with the axis of symmetry of the impedances of the chassis.
The impedances described above preferably have a specific value at the frequency of the RF power generated at the output of the RF generator.
In general, plasma treatment is performed at frequencies within the range from 13.56 MHz to 60 MHz. By adjusting the return path, such as a chassis, so that the impedances are axisymmetrically equal at a predetermined frequency in practical use within the above-mentioned range in the plasma processing apparatus, more uniform plasma treatment of the treatment surface of a workpiece, is achieved. Thus, the plasma processing apparatus is capable of preventing drift of the discharge current that flows through a gap between electrodes of an electrode pair during actual plasma discharge.
The present invention, in its second aspect, provides a plasma processing apparatus having a plasma processing chamber including an electrode for exciting plasma; an RF generator for supplying the electrode with RF power; and a matching circuit having an input terminal and an output terminal, for matching the impedance between the plasma processing chamber and the RF generator. The RF generator is connected to an RF supplier and the RF supplier is connected to the input terminal, the electrode is connected to an RF feeder and the RF feeder is connected to the output terminal, and a ground potential portion is connected between the input terminal and the output terminal. The matching circuit includes at least two inductance coils connected in parallel.
Such a structure of the plasma processing apparatus allows the parasitic RF resistance of the inductance coils in the matching circuit to be decreased, thereby reducing the power loss in the matching circuit.
In the plasma processing apparatus according to embodiments of the present invention, the inductance coils mentioned above are preferably arranged in parallel. It is also preferable that the inductance coils be axisymmetrically arranged with respect to the center of the electrodes.
Such a structure is preferable because the equilibrium state of the high-frequency current flowing through the inductance coils in the matching circuit is maintained, thereby reducing the parasitic RF resistance and achieving a stable plasma.
In the plasma processing apparatus according to embodiments of the present invention, the electrode for exciting plasma may also serve as an electrode of a tuning capacitor in the matching circuit. Thus, the apparatus is simplified and the parasitic RF resistance reduced.
Since the inductance coils of the matching circuit have a low parasitic RF resistance, low power loss is experienced in the matching circuit and increased effective power in the plasma space can be achieved.
The plasma processing apparatus according to the present invention is useful for efficiently performing plasma treatment such as CVD, sputtering, dry etching, or ashing.
The above and other objects, features, and advantages of the present invention will become clear from the following description of the preferred embodiments taken in conjunction with the accompanying drawings.
Although embodiments of the present invention will be described using specific examples, the present invention is not limited to such examples. The accompanying drawings are for illustrating the spirit of the present invention, and unnecessary elements are omitted for illustrative purposes. Elements shown in the drawings are not necessarily identical to actual elements in shape, size ratio, number, etc.
First Embodiment
The matching circuit 2A matches the impedance between the RF generator 1 and the plasma excitation electrode 4, and is accommodated in a chassis 2 formed of aluminum alloy plates. The top plate 2T of the chassis 2 is a square, as described in detail below, and the central axis of the top plate 2T is coincident with an axial line X--X of the plasma processing apparatus in FIG. 1.
The coaxial cable 1A extends from the center of the top plate 2T of the chassis 2 toward the RF generator 1. The RF feeder 3 and the plasma excitation electrode 4 are enclosed in a housing 21 formed of aluminum alloy plates as in the chassis 2. The housing 21 is cylindrically shaped and arranged such that the central axis thereof is coincident with the axial line X--X. The housing 21 is coupled to the chassis 2.
The housing 21 shares the axial line X--X with the chassis 2. Since the chassis 2 and the housing 21 are axially symmetric and are coupled to each other, these can be considered to be an integrated chassis.
The plasma processing apparatus includes a plasma excitation electrode 4 and a shower plate 5 provided in the upper portion of a plasma processing chamber 60. The susceptor electrode 8 that carries the workpiece W is in the lower portion of the chamber 60 and faces the shower plate 5. The susceptor electrode 8 is disc-shaped, and is arranged such that the central axis thereof is coincident with the axial line X--X. A chamber wall 10 surrounding the chamber 60 is also cylindrically shaped and is arranged such that the central axis thereof is coincident with the axial line X--X. The chamber wall 10 is coupled to the housing 21.
As described above, in the plasma processing apparatus according to the first embodiment shown in
The plasma excitation electrode 4 is connected to the power supply side of the RF generator 1 through the RF feeder 3, the matching circuit 2A, and the core of the coaxial cable 1A, as described above. A shaft 13 is connected to the center of the lower portion of the susceptor electrode 8. The shaft 13 extends downward through a chamber bottom 10A. The lower portion of the shaft 13 is hermetically sealed with the central portion of the chamber bottom 10A with conductive bellows 11. The susceptor electrode 8 and the shaft 13 can move vertically with the bellows 11 to adjust the distance between the plasma excitation electrode 4 and the susceptor electrode 8. The susceptor electrode 8 and the shaft 13 are electrically connected to the chamber bottom 10A. Therefore, the susceptor electrode 8, the shaft 13, the bellows 11, the chamber bottom 10A, the chamber wall 10, the housing 21, and the chassis 2 are electrically connected and have the same DC potential. The chassis 2 is connected to the shielding line (outer conductor) of the coaxial cable 1A. Since the shielding line is connected to the grounded common side of the RF generator 1, a return path from the susceptor electrode 8 to the RF generator 1 is DC-grounded.
The RF feeder 3 is composed of a silver-coated copper plate, which is, for example, 50 to 100 mm wide, 0.5 mm thick, and 100 to 300 mm long. The RF feeder 3 is detachably mounted to both the output terminal of a tuning capacitor 24, described below, in the matching circuit 2A and the plasma excitation electrode 4 with coupling means such as screws.
An annular projection 4a is provided on the bottom face of the plasma excitation electrode 4. A shower plate 5 having many holes 7 is in contact with the annular projection 4a below the plasma excitation electrode 4. The plasma excitation electrode 4 and the shower plate 5 define a space 6. A gas inlet pipe 17, which extends through a sidewall of the housing 21 and the plasma excitation electrode 4, communicates with the space 6. The gas inlet pipe 17 is formed of a conductive material and is provided with an insulator 17a in the middle thereof, inside the housing 21, for insulating the plasma excitation electrode 4 from the gas supply source. Gas from the gas inlet pipe 17 is introduced into the chamber 60 through the holes 7 of the shower plate 5. The chamber wall 10 and the plasma excitation electrode 4 are insulated from each other with an annular insulator 9. An exhaust system (not shown) is connected to the chamber 60.
The matching circuit 2A adjusts the impedance in accordance with, for example, changes in plasma state in the chamber 60. The matching circuit 2A is provided between the RF generator 1 and the RF feeder 3, as shown in FIG. 1. The matching circuit 2A has an inductance coil 23, a tuning capacitor 24 consisting of an air variable capacitor, and a load capacitor 22 consisting of a vacuum variable capacitor. The inductance coil 23 and the tuning capacitor 24 are connected in series in the named order from the input terminal to the output terminal of the matching circuit 2A, and the load capacitor 22 is provided between the input terminal of the inductance coil 23 and the chassis 2 (common potential portion). The inductance coil 23 and the tuning capacitor 24 are directly connected without an interposing conductor. The tuning capacitor 24 serves as the output terminal of the matching circuit 2A. The output terminal PR of the tuning capacitor 24 is connected to the plasma excitation electrode 4 through the RF feeder 3.
Referring to
All four sidewalls 38 of the chassis 2 serve as return paths of a high-frequency current HC flowing from the housing 21 to the RF generator 1 through the coaxial cable 1A. These sidewalls 38, which are paths of the high-frequency current HC, have impedances Z1, Z2, Z3, and Z4 depending on the frequency of the high-frequency current HC, as shown in FIG. 2B. In the plasma processing apparatus according to the first embodiment, at a frequency of 40.68 MHz generated at the output of the RF generator 1, the values of the impedances Z1, Z2, Z3, and Z4 are adjusted so as to be equal to each other. In other words, in the return paths in the chassis 2, the impedances Z1, Z2, Z3, and Z4 at a predetermined frequency (for example, 40.68 MHz) of the RF power are axisymmetrically equal about the axis of symmetry, that is, the axial line X--X, with respect to the direction of the current returning to the RF generator 1. Similarly, according to this embodiment, also in the return paths in the housing 21, impedances at a predetermined frequency (e.g., 40.68 MHz) are axisymmetrically equal about the axis of symmetry, that is, the axial line X--X.
Referring to
An embodiment in which the workpiece W is plasma-treated using the plasma processing apparatus according the first embodiment will now be described. Referring to
At this time, a potential difference corresponding to the discharge voltage is generated between the plasma excitation electrode 4 and the susceptor electrode 8. Each of the shaft 13, the bellows 11, the chamber bottom 10A, the chamber wall 10, the housing 21, the chassis 2, and the shielding line of the coaxial cable 1A, serving as the return path from the susceptor electrode 8 to the common side of the RF generator 1, has AC resistance, that is, impedance. Therefore, while the susceptor electrode 8 is DC-grounded, it has a potential corresponding to the current flowing through the above impedance for AC voltage. Accordingly, a high-frequency current flows from the susceptor electrode 8 to the common side of the RF generator 1. This high-frequency current flows over the surface of conductive components such as the chamber wall 10, the housing 21, and the chassis 2.
Referring to
Since the chassis 2 and the housing 21 are axisymmetric about the axial line X--X and are electrically connected, all the cross-sections perpendicular to the axial line X--X become axisymmetric, even when the top plate 2T of the chassis 2 is a square and the housing 21 is a cylinder, so that the chassis 2 and the housing 21 can be considered to be an integrated chassis. Furthermore, as long as the quality of the materials thereof is uniform, in a structure (chassis in a broad sense) in which the chassis 2 and the housing 21 are integrated, the impedances are axisymmetrically equal about the axis of symmetry, that is, the axial line X--X, with respect to the direction of the current returning to the RF generator 1.
According to the first embodiment, since the susceptor electrode 8 and the chamber wall 10 are also axisymmetrically equal about the axial line X--X and the coaxial cable 1A extends from the center of the top plate 2T of the chassis 2, as described above, factors causing drift in the return path of the high-frequency current are almost eliminated, thereby achieving uniform plasma treatment of the workpiece W.
Second Embodiment
A second embodiment of the present invention includes various modifications to the shape of the chassis. Since the features other than the shape of the chassis and the arrangements thereof are the same as in the first embodiment, detailed descriptions thereof are omitted here.
A copper plate Cu is bonded to the surface of the sidewall 38A. Since the copper plate Cu has an impedance smaller than the stainless steel plate, the impedance Z1 of the sidewall 38A can be substantially reduced. Slits 39 are formed on the sidewalls 38B and 38D in a direction blocking the path of the high-frequency current. The formation of the slits allows the impedances Z2 and Z4 of the sidewalls 38B and 38D to substantially increase. As described above, according to the modification shown in
Although, in the plasma processing apparatuses of the present invention described above, base materials such as the chassis 2, the housing 21, and the chamber wall 10 are ordinarily aluminum or stainless steel, a low-resistance conductive path having a lower resistance with respect to the high-frequency current may be provided on the surfaces thereof. The provision of the low-resistance conductive path can further reduce the loss of RF power supplied to the plasma generation space. This low-resistance conductive path is preferably made of gold, silver, copper, or an alloy containing at least such materials. The low-resistance conductive path may be formed such that it covers the surface of each of the above components. One or more linear or zonal low-resistance conductive paths, which run from the susceptor electrode 8 to the RF generator 1 through the surfaces of such components, may be provided.
In the plasma processing apparatus according to the present invention, the surfaces of the chassis 2, the housing 21, the chamber wall 10, the chamber bottom 10A, the bellows 11, and so on may be covered with an insulating film if required. An insulating film made of polyimide, PFA (tetrafluoroethylene-perfluoroalkylvinylether copolymer), PTFE (polytetrafluoroethylene), ETFE (tetrafluoroethylene-ethylene copolymer), or the like is used. The polyimide, the PFA (tetrafluoroethylene-perfluoroalkylvinylether copolymer), and the PTFE (polytetrafluoroethylene) have superior heat resistance, whereas the ETFE (tetrafluoroethylene-ethylene copolymer) has superior abrasion resistance. Accordingly, it is preferable to selectively use a material appropriate to the application or to form a multi-layer film.
In the plasma processing apparatus according to the present invention, RF power preferably with a frequency of 13.56 MHz or more, specifically with a frequency of, for example, 13.56 MHz, 27.12 MHz, or 40.68 MHz, can be fed to the apparatus to produce a plasma between the electrodes of the electrode pair 14. With this plasma, plasma treatment such as CVD, dry etching, or ashing can be performed on the workpiece W held on the susceptor electrode 8.
When plasma treatment such as reactive ion etching (RIE) is performed, the workpiece W may be mounted to the plasma excitation electrode 4, instead of being placed on the susceptor electrode 8. An inductively coupled plasma (ICP) excitation electrode pair or a radial line slot antenna (RLSA) electrode pair may be used instead of the parallel plate electrode pair. Accordingly, the scope of the present invention is not to be limited by the illustrative examples provided but is intended to extend to all forms of plasma treatments.
In the plasma processing apparatus constructed as described above, an operator sets various processing conditions such as deposition conditions, annealing conditions, and heat treatment conditions, and a processing sequence which are appropriate for the workpiece W. However, the operation of individual components is controlled by a controller unit (not shown) and the apparatus is automatically operated. Therefore, in the plasma processing apparatus, when the operator operates a start switch after the workpiece W to be treated is set in a loading cassette (not shown), a carrier robot carries the workpiece W form the loading cassette into the chamber 60. After a series of processes are automatically and sequentially performed in the chamber 60, the carrier robot sets the treated workpiece W in an unloading cassette.
Third Embodiment
Since the main structure of the plasma processing apparatus according to the third embodiment is similar to that of the conventional plasma processing apparatuses shown in
In the plasma processing apparatus according to the third embodiment shown in
The two inductance coils 23a and 23b are provided in parallel and are axisymmetrically arranged with respect to the center of a plasma excitation electrode 4, that is, they are axisymmetrically arranged with respect to the center of an RF feeder 3.
The two inductance coils 23a and 23b are axisymmetrically arranged with respect to the center 40 of the plasma excitation electrode 4. They are spatially provided in parallel and electrically connected in parallel.
Although two inductance coils are shown in the third embodiment, the number thereof is not limited to two; more than two inductance coils may be used and still be in keeping with the spirit and scope of the present invention.
Provision of a plurality of inductance coils, axisymmetrically and in parallel with respect to the center 40 of the plasma excitation electrode 4, allows the parasitic RF resistance to be reduced, thereby achieving low power loss in the matching circuit 2A.
Fourth Embodiment
In the plan view according to the fourth embodiment in
Such an arrangement of the inductance coils contributes to a further reduction in the parasitic RF resistance, thereby achieving low power loss in the matching circuit 2A.
Fifth Embodiment
In the plan view according to the fifth embodiment in
Such an arrangement of the inductance coils contributes to a further reduction in the parasitic RF resistance, thereby achieving low power loss in the matching circuit 2A.
Sixth Embodiment
In the plasma processing apparatus according to the sixth embodiment, a plasma chamber 76 is structured such that a plasma excitation electrode 4 for exciting plasma also functions as one electrode of the tuning capacitor 24 in the matching circuit 2A for matching the impedance with the RF generator 1 in the plasma processing apparatus according to the third embodiment.
Other components are the same as in the third embodiment shown in FIG. 8. Although two inductance coils 23a and 23b are shown, as in the third embodiment, the number of inductance coils may be more than two.
Such a structure of the matching circuit provides an advantage in that the effect of a plurality of inductance coils is maintained in a simplified apparatus, thereby attaining a further reduction in the parasitic RF resistance.
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